This invention relates to an apparatus for examination of the eye, and in particular, to such an apparatus adapted for examination of the retina, vitreous, pigment epithelium, choroid, cornea, anterior chamber, iris, crystalline lens and anterior vitreous of the human eye. More specifically, this invention relates to a binocular ophthalmoscope having head gear to be worn on an examiner's source for illuminating a patient's eye. The light source is laterally movable to permit illumination of the patient's eye from various angles with respect to the optical viewing system. The viewing system may be a binocular indirect ophthalmoscope which is used in conjunction with a hand held condensing lens to view an aerial or indirect image of the eye; a binocular biomicroscope for a direct microscopic view of the eye; or a binocular biomicroscope which is used together with a hand held condensing lens, for viewing an enlarged aerial image of the eye. The laterally movable light source is adapted to provide both slit beam and full beam illumination of the patient's eye.
The invention may be used to provide a fullbeam illuminated view to conduct examination of the fundus for retinal mapping or for full field viewing of the cornea, anterior chamber, iris, crystalline lens or vitreous. The invention may be used to provide a centered or angulated slit directly illuminated view of the retina and of the vitreous to detect vitreous attachments, retinal discontinuities, tumors of the choroid or pigment epithelium. Additionally, the invention may be used to provide a centered or angulated slit retro-illuminated view of the retina and vitreous gel to provide, in effect, a "back lighted " view of the posterior segment of the eye. Further, the invention permits the examiner to perform ophthalmoscopy of the vitreous and peripheral retina using simultaneously a slit beam light source together with manual scleral depression.
Binocular ophthalmoscopes of various types have been long known in the art, but their usefulness and flexibility have generally been restricted to use in examination of only a limited portion of the eye, or have involved the use of bulky equipment and of cumbersome and uncomfortable contact lenses on the patient's eye. None of these instruments permit a practical examination of the relationship of the peripheral retina to the vitreous. Further, none of these instruments permits a practical examination of the vitreous and peripheral retina by simultaneous use of slit beam illumination and scleral depression. For example, binocular indirect ophthalmoscopes of the type illustrated in U.S. Pat. No. 3,582,191 to Cohen; U.S. Pat. No. 3,963,329 to Stumpf et al; and U.S. Pat. No. 2,757,574 to Thornburn may be used only to view the retina of the eye, are incapable of slit beam or retro illumination and cannot be used for examination of the diaphanous vitreous or other anterior portions of the eye. Conventional slit lamp biomicroscopes such as illustrated in U.S. Pat. No. 3,652,153 to Gambs or U.S. Pat. No. 3,403,957 to Wilkinson are incapable of examining the retina, vitreous body, posterior hyaloid or other posterior portions of the eye without use of a Goldmann contact lens or an auxiliary mounted Hruby lens to eliminate corneal refraction. Both the Goldmann corneal contact lens and the mounted Hruby lens present significant disadvantages to the examination of a patient. The Goldman contact lens is cumbersome and uncomfortable and requires anesthetization of the patient's cornea. Moreover, it may not conveniently be used with scleral depression which is required to bring the peripheral retina into view. The mounted Hruby lens has a very limited field of view permitting examination only of the posterior retina and optic nerve. Also, since the Hruby lens is fixed relative to the biomicroscope and the patient is generally stationary relative to the biomicroscope, the examiner cannot follow movement of the patient's eye and cannot view the retinal periphery with slit beam illumination.